You have lots of time to worry about there. There are certain characteristics that tend to surface in many specialties, but there are plenty of exceptions. I'm currently on my surgery rotation. The only thing I can do is get as much exposure to all the fields that I can. I scrub general surgery, uro, ortho, ent, do intubations, start IVs and central lines and talk anesthesia. You get a feel rather quickly for what you like.
I personally love orthopedics. I do fit the whole " big jock" image commonly associated with it, but the surgeons I've been with haven't fit that mold.